Kilogram-Scale Production of Biodegradable Poly(butylene carbonate): Molecular Weight Dependence of Physical Properties and Enhanced Crystallization by Nucleating Agent

The creation of DMC-based biodegradable materials with excellent properties is a potential and sustainable option now that the industrial production of dimethyl carbonate (DMC) synthesis from carbon dioxide is commercially feasible. Herein, a series of kilogram-scale DMC-based biodegradable poly(butylene carbonate) (PBC) with distinct molecular weight gradients (number average molecular weight (M-n) varied from 23 to 67 kg/mol) were synthesized successfully through a facile melt polycondensation reaction using a 5 L stainless steel reactor. The microstructure of the polymers was confirmed by FTIR and H-1 NMR. It was thoroughly discussed how molecular weight affected the physical performance of PBC, including thermal properties, rheological behaviors, mechanical characteristics, and degradation behaviors. The findings indicated that the molecular weight had significant influence on the physical characteristics of PBC. Especially, PBC with M-n greater than 46 kg/mol showed excellent mechanical strength and elongation at break with the values of 37.3 MPa and 559.1%, respectively. All the PBCs exhibited appreciable biodegradability under enzymatic degradation. In addition, as a novel and environmentally acceptable nucleating agent, magnesium mandelate (Mg(MdA)(2)) was introduced into PBC via melt blending. The non-isothermal behaviors and isothermal crystallization kinetics of the PBC/Mg(MdA)(2) were specially forced. It was discovered that Mg(MdA)(2) greatly accelerated both the non-isothermal and isothermal crystallization of PBC and exhibited a prominent nucleation activity on the crystallization of PBC. Moreover, the WAXD patterns of all the blend samples displayed the same distinctive peaks as neat PBC, proving that the structure of the PBC crystals had no modification with the addition of Mg(MdA)(2). Accordingly, the current work proposed enlarged step-by-step synthesis of PBC material and physical modification which highlighted the technical feasibility of PBC industrial production and expansion of processing molding applications.

Automated summary

A series of kilogram-scale DMC-based biodegradable PBCs with different molecular weight gradients were successfully synthesized through a facile melt polycondensation reaction. The molecular weight was found to significantly influence the physical characteristics of PBC, and PBC with a higher molecular weight exhibited excellent mechanical strength and elongation at break. Furthermore, the introduction of magnesium mandelate as a nucleating agent greatly accelerated the crystallization of PBC and showed a prominent nucleation activity.